Fix/130 ignore socket errors

docs/reference.rst

@@ -14,7 +14,7 @@ server supports.
     information.
 
 
-.. py:class:: StatsClient(host='localhost', port=8125, prefix=None, maxudpsize=512)
+.. py:class:: StatsClient(host='localhost', port=8125, prefix=None, maxudpsize=512, ignore_socket_errors=False)
 
     Create a new ``StatsClient`` instance with the appropriate connection and
     prefix information.
@@ -27,11 +27,22 @@ server supports.
     :param int maxudpsize: the largest safe UDP packet to send. 512 is
         generally considered safe for the public internet, but private networks
         may support larger packet sizes.
+    :param bool ignore_socket_errors: whether or not to ignore socket errors
+        when initializing the client. If set to ``True``, the client will ignore
+        the error and continue. If set to ``False``, the client will raise the error.
+        You can check the ``is_ready`` attribute to see if the client is ready to send.
 
 .. py:method:: StatsClient.close()
 
     Close the underlying UDP socket.
 
+.. py:method:: StatsClient.reset()
+
+    Resets the underlying UDP socket. This is useful if the connection is
+    not ready due to network issues or if the connection was closed. This
+    method will honor the ``ignore_socket_errors`` parameter in the constructor.
+    You can check the ``is_ready`` attribute to see if the client is ready to send.
+
 .. py:method:: StatsClient.incr(stat, count=1, rate=1)
 
     Increment a :ref:`counter <counter-type>`.

statsd/client/base.py

@@ -8,6 +8,15 @@
 class StatsClientBase:
     """A Base class for various statsd clients."""
 
+    @property
+    def is_ready(self):
+        """Returns True if the client is ready to send data."""
+        raise NotImplementedError()
+
+    def reset(self):
+        """Reset the client."""
+        raise NotImplementedError()
+
     def close(self):
         """Used to close and clean up any underlying resources."""
         raise NotImplementedError()

statsd/client/stream.py

@@ -18,6 +18,9 @@ def close(self):
             self._sock.close()
         self._sock = None
 
+    def reset(self):
+        self.reconnect()
+
     def reconnect(self):
         self.close()
         self.connect()
@@ -48,6 +51,11 @@ def __init__(self, host='localhost', port=8125, prefix=None,
         self._prefix = prefix
         self._sock = None
 
+    @property
+    def is_ready(self):
+        """Return True if the client is ready to send data."""
+        return self._sock is not None
+
     def connect(self):
         fam = socket.AF_INET6 if self._ipv6 else socket.AF_INET
         family, _, _, _, addr = socket.getaddrinfo(
@@ -67,6 +75,11 @@ def __init__(self, socket_path, prefix=None, timeout=None):
         self._prefix = prefix
         self._sock = None
 
+    @property
+    def is_ready(self):
+        """Return True if the client is ready to send data."""
+        return self._sock is not None
+
     def connect(self):
         self._sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
         self._sock.settimeout(self._timeout)

statsd/client/udp.py

@@ -26,15 +26,39 @@ class StatsClient(StatsClientBase):
     """A client for statsd."""
 
     def __init__(self, host='localhost', port=8125, prefix=None,
-                 maxudpsize=512, ipv6=False):
+                 maxudpsize=512, ipv6=False, ignore_socket_errors=False):
         """Create a new client."""
-        fam = socket.AF_INET6 if ipv6 else socket.AF_INET
-        family, _, _, _, addr = socket.getaddrinfo(
-            host, port, fam, socket.SOCK_DGRAM)[0]
-        self._addr = addr
-        self._sock = socket.socket(family, socket.SOCK_DGRAM)
+        self._host = host
+        self._port = port
+        self._ipv6 = ipv6
         self._prefix = prefix
         self._maxudpsize = maxudpsize
+        self._addr = None
+        self._sock = None
+        self._ignore_socket_errors = ignore_socket_errors
+        self._ready = False
+        self._open()
+
+    @property
+    def is_ready(self):
+        """Return True if the client is ready to send data."""
+        return self._ready
+
+    def _open(self):
+        fam = socket.AF_INET6 if self._ipv6 else socket.AF_INET
+
+        try:
+            family, _, _, _, addr = socket.getaddrinfo(
+                self._host, self._port, fam, socket.SOCK_DGRAM)[0]
+            self._addr = addr
+            self._sock = socket.socket(family, socket.SOCK_DGRAM)
+            self._prefix = self._prefix
+            self._maxudpsize = self._maxudpsize
+            self._ready = True
+        except (socket.gaierror, OSError):
+            if not self._ignore_socket_errors:
+                raise
+            self._ready = False
 
     def _send(self, data):
         """Send data to statsd."""
@@ -44,6 +68,10 @@ def _send(self, data):
             # No time for love, Dr. Jones!
             pass
 
+    def reset(self):
+        self.close()
+        self._open()
+
     def close(self):
         if self._sock and hasattr(self._sock, 'close'):
             self._sock.close()

statsd/tests.py

@@ -1,5 +1,6 @@
 import asyncio
 import functools
+import os
 import random
 import re
 import socket
@@ -35,12 +36,18 @@ def eq_(a, b, msg=None):
     assert a == b, msg
 
 
-def _udp_client(prefix=None, addr=None, port=None, ipv6=False):
+def _is_travis():
+    return os.environ.get('TRAVIS') in ('true', '1')
+
+
+def _udp_client(prefix=None, addr=None, port=None, ipv6=False,
+                ignore_socket_errors=False):
     if not addr:
         addr = ADDR[0]
     if not port:
         port = ADDR[1]
-    sc = StatsClient(host=addr, port=port, prefix=prefix, ipv6=ipv6)
+    sc = StatsClient(host=addr, port=port, prefix=prefix, ipv6=ipv6,
+                     ignore_socket_errors=ignore_socket_errors)
     sc._sock = mock.Mock()
     return sc
 
@@ -268,20 +275,47 @@ def _test_resolution(cl, proto, addr):
     _sock_check(cl._sock, 1, proto, 'foo:1|c', addr=addr)
 
 
+def test_ipv6_resolution_tcp():
+    cl = _tcp_client(addr='localhost', ipv6=True)
+    _test_resolution(cl, 'tcp', ('::1', 8125, 0, 0))
+
+
 def test_ipv6_resolution_udp():
-    raise SkipTest('IPv6 resolution is broken on Travis')
+    if _is_travis():
+        raise SkipTest('IPv6 resolution is broken on Travis')
     cl = _udp_client(addr='localhost', ipv6=True)
     _test_resolution(cl, 'udp', ('::1', 8125, 0, 0))
+    assert cl.is_ready is True
 
 
-def test_ipv6_resolution_tcp():
-    cl = _tcp_client(addr='localhost', ipv6=True)
-    _test_resolution(cl, 'tcp', ('::1', 8125, 0, 0))
+def test_ipv6_error_in_resolution_udp():
+    if _is_travis():
+        raise SkipTest('IPv6 resolution is broken on Travis')
+    with assert_raises(socket.gaierror):
+        _ = _udp_client(addr='fakehost', ipv6=True)
+
+
+def test_ipv6_error_in_resolution_ignored_udp():
+    if _is_travis():
+        raise SkipTest('IPv6 resolution is broken on Travis')
+    cl = _udp_client(addr='fakehost', ipv6=True, ignore_socket_errors=True)
+    assert cl.is_ready is False
 
 
 def test_ipv4_resolution_udp():
     cl = _udp_client(addr='localhost')
     _test_resolution(cl, 'udp', ('127.0.0.1', 8125))
+    assert cl.is_ready is True
+
+
+def test_ipv4_error_in_resolution_udp():
+    with assert_raises(socket.gaierror):
+        _ = _udp_client(addr='fakehost')
+
+
+def test_ipv4_error_in_resolution_ignored_udp():
+    cl = _udp_client(addr='fakehost', ignore_socket_errors=True)
+    assert cl.is_ready is False
 
 
 def test_ipv4_resolution_tcp():